In a conventional crystalline silicon solar cell module, a mono-facial cell is selected for a module package. However, the above cell module is easily limited by landscapes and ground objects, thereby resulting in problems such as low power generation, low efficiency, and high cost. A novel cell module for a bifacial cell has been developed thanks to battery plate improvements. The module of the battery plate is becoming a desirable product in this industry because it may enhance the efficiency of power generation and reduce the cost of installation.
The package module of the bifacial cell is still formed by the traditional package method, in which a front sheet such as glass, an encapsulant such as ethylene vinyl acetate copolymers (EVA), a bifacial solar cell, another encapsulant such as EVA, and a back sheet such as glass are arranged from top to bottom. The encapsulant functions include fixing the solar cell, connecting the circuit line, and providing insulation protection for the solar cell. In addition, the cell performance should overcome the surrounding test even after long-term use through the encapsulant. The back sheet may provide electrical insulation, water resistance, high temperature resistance, and high moisture resistance to lengthen the lifetime of the solar cell module.
The module for the bifacial cell should adopt a transparent glass or a transparent back sheet to meet the requirements of power generation from the back-side exposure in practice. However, the glass may increase the total cost of the module system due to its weight. As a result, glass cannot be widely used. The plastic substrate may simultaneously have the following properties: high light transmittance, high water and gas proofing, and excellent climate resistance. Moreover, whatever material is selected for the back sheet, it should have an excellent adhesion in the module, as well as be able to protect the cell.